在Xamarin Android應用程序中使用DataContractJsonSerializer時，版本版本會崩潰

Question

為了理解該問題，我創建了一個普通的空白Xamarin Android應用。 通過以下簡單的代碼，我可以在按下按鈕時使應用程序的發行版崩潰。 請注意，為了進行構建，我需要添加對System.Runtime.Serialization的引用：

   protected override void OnCreate(Bundle bundle)
   {
        base.OnCreate(bundle);

        // Set our view from the "main" layout resource
        SetContentView(Resource.Layout.Main);

        // Get our button from the layout resource,
        // and attach an event to it
        Button button = FindViewById<Button>(Resource.Id.MyButton);

        button.Click += delegate
        {
            using (MemoryStream stream = new MemoryStream())
            {
                DateTimeOffset offset = new DateTimeOffset(DateTime.Now);
                string serializedOffset;

                var serializer = new DataContractJsonSerializer(typeof(DateTimeOffset));
                Log.Info(nameof(MainActivity), "HACKAGE:about to serialize");
                serializer.WriteObject(stream, offset);
                serializedOffset = Encoding.UTF8.GetString(stream.ToArray(), 0, (int)stream.Position);
                Log.Info(nameof(MainActivity), "HACKAGE: got serialized" + serializedOffset);
            }
            button.Text = string.Format("{0} clicks!", count++);
        };
    }
    static void ExistenceCausesCrash(string serializedObject)
    {
        DateTimeOffset resultEx;
        var serializer = new DataContractJsonSerializer(typeof(DateTimeOffset));
        byte[] serializedObjectBytes = Encoding.UTF8.GetBytes(serializedObject);
        using (var stream = new MemoryStream(serializedObjectBytes))
        {
            resultEx = (DateTimeOffset)serializer.ReadObject(stream);
        }
    }

有趣的是：如果我注釋掉ExistenceCausesCrash()例程，則應用程序不會崩潰。

我在用：

    Microsoft Visual Studio Enterprise 2015
    Version 14.0.24720.00 Update 1
    Microsoft .NET Framework
    Version 4.6.01038

    Xamarin   4.0.0.1717 (1390b70)
    Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android.

    Xamarin.Android   6.0.0.35 (d300845)
    Visual Studio plugin to enable development for Xamarin.Android.

    Xamarin.iOS   9.3.99.33 (ea30b32)
    Visual Studio extension to enable development for Xamarin.iOS.

在我看來，這是在我升級到4.0.0.1717時開始發生的

在logcat中，我看到：

    01-06 12:32:01.850: I/MonoDroid(18126): UNHANDLED EXCEPTION:
    01-06 12:32:01.861: I/MonoDroid(18126): System.Runtime.Serialization.InvalidDataContractException: No set method for property 'OffsetMinutes' in type 'System.Runtime.Serialization.DateTimeOffsetAdapter'.
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.DataContract+DataContractCriticalHelper.ThrowInvalidDataContractException (System.String message, System.Type type) [0x0007b] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.DataContract.ThrowInvalidDataContractException (System.String message, System.Type type) [0x00000] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.JsonFormatWriterInterpreter.WriteToJson (System.Runtime.Serialization.XmlWriterDelegator xmlWriter, System.Object obj, System.Runtime.Serialization.Json.XmlObjectSerializerWriteContextComplexJson context, System.Runtime.Serialization.ClassDataContract dataContract, System.Xml.XmlDictionaryString[] memberNames) [0x00051] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.JsonFormatWriterGenerator+CriticalHelper+<GenerateClassWriter>c__AnonStorey0.<>m__0 (System.Runtime.Serialization.XmlWriterDelegator xmlWriter, System.Object obj, System.Runtime.Serialization.Json.XmlObjectSerializerWriteContextComplexJson context, System.Runtime.Serialization.ClassDataContract dataContract, System.Xml.XmlDictionaryString[] memberNames) [0x0000b] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.JsonClassDataContract.WriteJsonValueCore (System.Runtime.Serialization.XmlWriterDelegator jsonWriter, System.Object obj, System.Runtime.Serialization.Json.XmlObjectSerializerWriteContextComplexJson context, RuntimeTypeHandle declaredTypeHandle) [0x00027] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.JsonDataContract.WriteJsonValue (System.Runtime.Serialization.XmlWriterDelegator jsonWriter, System.Object obj, System.Runtime.Serialization.Json.XmlObjectSerializerWriteContextComplexJson context, RuntimeTypeHandle declaredTypeHandle) [0x00007] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.DataContractJsonSerializer.WriteJsonValue (System.Runtime.Serialization.Json.JsonDataContract contract, System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph, System.Runtime.Serialization.Json.XmlObjectSerializerWriteContextComplexJson context, RuntimeTypeHandle declaredTypeHandle) [0x00000] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.XmlObjectSerializerWriteContextComplexJson.WriteDataContractValue (System.Runtime.Serialization.DataContract dataContract, System.Runtime.Serialization.XmlWriterDelegator xmlWriter, System.Object obj, RuntimeTypeHandle declaredTypeHandle) [0x0003d] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeAndVerifyType (System.Runtime.Serialization.DataContract dataContract, System.Runtime.Serialization.XmlWriterDelegator xmlWriter, System.Object obj, Boolean verifyKnownType, RuntimeTypeHandle declaredTypeHandle, System.Type declaredType) [0x0007a] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.XmlObjectSerializerWriteContextComplexJson.SerializeWithXsiTypeAtTopLevel (System.Runtime.Serialization.DataContract dataContract, System.Runtime.Serialization.XmlWriterDelegator xmlWriter, System.Object obj, RuntimeTypeHandle originalDeclaredTypeHandle, System.Type graphType) [0x00066] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.DataContractJsonSerializer.InternalWriteObjectContent (System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph) [0x00110] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.DataContractJsonSerializer.InternalWriteObject (System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph) [0x00008] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.XmlObjectSerializer.InternalWriteObject (System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph, System.Runtime.Serialization.DataContractResolver dataContractResolver) [0x00000] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.XmlObjectSerializer.WriteObjectHandleExceptions (System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph, System.Runtime.Serialization.DataContractResolver dataContractResolver) [0x00079] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.XmlObjectSerializer.WriteObjectHandleExceptions (System.Runtime.Serialization.XmlWriterDelegator writer, System.Object graph) [0x00000] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.DataContractJsonSerializer.WriteObject (System.Xml.XmlDictionaryWriter writer, System.Object graph) [0x0000d] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at System.Runtime.Serialization.Json.DataContractJsonSerializer.WriteObject (System.IO.Stream stream, System.Object graph) [0x00018] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at XamarinDateTimeOffsetBugApp1.MainActivity+<>c__DisplayClass1_0.<OnCreate>b__0 (System.Object <sender>, System.EventArgs <e>) [0x00030] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at Android.Views.View+IOnClickListenerImplementor.OnClick (Android.Views.View v) [0x00014] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at Android.Views.View+IOnClickListenerInvoker.n_OnClick_Landroid_view_View_ (IntPtr jnienv, IntPtr native__this, IntPtr native_v) [0x00011] in <filename unknown>:0 
    01-06 12:32:01.861: I/MonoDroid(18126):   at (wrapper dynamic-method) System.Object:0d369c4c-eddc-4ca3-ad2e-8d81a770584b (intptr,intptr,intptr)

Answer 1

我認為這是由於Xamarin.Android鏈接過於激進。 Xamarin的cycle 7版本仍然會發生這種情況。 我們遇到了同樣的問題，目前通過添加解決此問題

<AndroidLinkSkip>System.Runtime.Serialization</AndroidLinkSkip>

在Android csproj文件中進行Release配置。

等待Xamarin更新並為此進行適當的修復...請參閱https://bugzilla.xamarin.com/show_bug.cgi?id=37491

Answer 2

您的問題在這里：

沒有為類型“ System.Runtime.Serialization.DateTimeOffsetAdapter”設置屬性“ OffsetMinutes”的方法。

檢查您是否在使用電話的地方進行通話。

如果在執行發行版本時使用的是proguard，請確保不會刪除引起問題的方法。

另外，請檢查此帖子以獲取其他用戶報告的相同異常的答案。